1. Field of the Invention
The present invention generally relates to power reduction in an electronic device. More particularly, the invention relates to reducing power in a notebook computer that has a wireless communication device connected thereto. Still more particularly, the invention relates to techniques for reducing power consumption in a battery-operated notebook having a digital interface to a wireless module that does not have a physical interrupt signal to permit the wireless module to alert the notebook computer of the presence of incoming data from the wireless network.
2. Background Information
As is commonly known, computers can be networked together to permit information to be transferred from one computer to another. Historically, the communication mechanism across the network has required a direct electrical connection to each computer over which data, commands and status information can be transferred. More recently, wireless communication modules have been developed to enable wireless networks.
Such wireless communication modules typically include an antenna, a transceiver, and a digital interface to the host computer. A typical wireless module is provided in the form of a circuit card which inserts into the side of notebook computer. An example of such a wireless module is a PCMCIA card which generally is slightly larger than a credit card and easily mates with the notebook through a PCMCIA card expansion slot which many notebooks include.
More recently, at least one computer manufacturer, Compaq Computer Corporation, has introduced a wireless module for a notebook computer in the form of a “MultiPort” device. A MultiPort module contains an antenna and wireless assembly in one package that mates with the rear surface of a notebook's display. Several advantages are obtained by placing the wireless electronics on the rear surface of the display including enhanced signal strength, greater throughput/speed, reduced susceptibility to externally generated noise, no protruding antenna to break off (PCMCIA card wireless modules typically have the antenna portion of the card protrude from the side of the notebook), and a reduced specific absorption rate. Compaq Computer Corp. currently has MultiPort modules available with a Universal Serial Bus (“USB”) interface to the host notebook computer.
Notebook computers and other portable devices can operate either from alternating current (“AC”) power through a power converter or from a battery. For obvious reasons, it is highly desirable for the batteries to power the notebook for as long as possible. All else being equal, however, adding additional features, devices and processing capabilities to notebook computers causes an increased power drain on the battery, thereby shortening battery life and requiring more frequent recharging. Accordingly, there is a constant tension when designing portable battery-operated electronic devices between performance on one hand and battery life on the other hand.
It has been observed that a battery in a notebook with a MultiPort wireless module has a shorter life than a comparable notebook with a PCMCIA card-based wireless module. Although the reduced battery life may not be excessively detrimental from the viewpoint of some users, it would be desirable not to have a reduction in battery life at all when using a MultiPort (or similar) wireless module. Accordingly, a solution to this problem is needed.